According to the specification of 3GPP TS 22.060, GPRS is introduced to a GSM network so that the 2nd mobile communication system can provide data service while providing conventional voice service. Hence, the mobile communication system is upgraded from 2 G to 2.5 G.
Data service is implemented in a radio access BSS by introducing two processing units, that is, a Packet Control Unit (PCU) and a Channel Coding Unit (CCU).
Referring to FIG. 1, a GPRS BSS is comprised of a Base Transceiver Station (BTS) 2 having a number of CCUs 21, a Base Station Controller (BSC) 1 and a PCU 32 and mainly used for processing of packet data carrying service at a BSS side and management of packet radio channel resources, wherein for the BSC, external interfaces comprises an ABIS interface from the BTS, an Ater Circuit Switching (CS) interface from Mobile Switching Center (MSC) and an Ater Packet Switching (PS) interface from PCU. The BSC is connected to PCU by E1 lines (base cluster interface with rate of 2048 kbit/s)
In an existing mode of network, the BSC is completely separated from the PCU or the PCU processing unit is embedded into the network unit such as BSC.
With respect to the above field BSS system, in order to smoothly support GPRS service, an existing means for processing is to introduce a network unit—Multi-BSSFast Packet Server (MFS). Referring to FIG. 1, a MFS server 3 may include a plurality of PCU processing units 31, where the MFS is a structure with one or more telecom subracks, with each subrack accommodating multiple GPRS Processing Units (GPUs) or other types of Packet Control Units (PCUs). In one example, an MFS includes one or two precabled telecom racks, with each subrack accommodating up to 11 GPU type PCUs as for example known as an Evolium Multi-BSS Fast Packet Server.
However, it is one of interests of the applicant how to provide a more flexible scheme for system network.